The present invention disclosed herein relates to methods of manufacturing nitride semiconductor devices, and more particularly, to methods of manufacturing ultra-thin nitride semiconductor devices.
A GaN-based compound semiconductor, which is a direct-transition-type semiconductor, allows emission of light of a wide range of wavelengths, e.g., from visible rays to ultraviolet rays. Compared to typical GaAs- or InP-based compound semiconductors, the GaN-based compound semiconductor has excellent properties such as high thermal/chemical stability, high electron mobility, high saturated electron velocity, and large energy bandgap. Due to such properties, GaN-based compound semiconductors are widely applied to the fields where the use of typical compound semiconductors is limited. For example, the GaN-based compound semiconductors are applied to optical devices such as visible light-emitting diodes (LEDs) and laser diodes (LDs) and electronic devices used in next-generation wireless communication or satellite communication systems required to have high power and high frequency characteristics. In particular, a nitride semiconductor (AlxInyGa1-x-yN) including aluminum (Al) is a next-generation nitride semiconductor material that may be used to manufacture a light-emitting device for the entire wavelength range of ultraviolet rays due to a high energy bandgap characteristic (3.4 eV-6.2 eV) of the nitride semiconductor. Furthermore, in the case where the nitride semiconductor forms a heterostructure (AlGaN/GaN, InAlN/GaN) together with GaN, an electronic device may be manufactured using a two-dimensional electron gas (2DEG) layer.
Various researches have been conducted to improve breakdown voltage characteristics of power semiconductor devices having a GaN-on-Si structure for which a bulk silicon substrate is used as a handle wafer. However, it has not been reported that GaN-based power semiconductor devices having a breakdown voltage of 600 V or higher have been commercialized. It may be important to develop a technology for manufacturing GaN-based power semiconductor devices having a high breakdown voltage so as to improve the GaN-based power semiconductor devices over Si- or SiC-based power semiconductor devices.
Furthermore, it is required to develop a technology for developing GaN-based power semiconductor devices having excellent electrical performance at a high temperature without being degraded in terms of electrical characteristics under a thermal environment, and having high breakdown voltage and improved characteristics of forward high current.